1. Field of the Invention
This invention relates to a tape recorder and more particularly to a tape recorder which is capable of varying a tape speed.
2. Description of the Related Art
With regard to a video tape recorder (hereinafter referred to as a VTR) having editing functions, the functions for speedily finding a position where editing is performed on a tape, i.e., an editing point, include a jog function, a shuttle function and a variable function.
These functions are generally arranged to be carried out with a tape transporting action controlled by operating and turning a dial which is provided on an operation panel of the VTR.
First, in the case of the jog function, a tape transport speed varies with the rotation speed of the dial. In other words, the tape is transported at a high speed when the dial is turned at a high speed. The tape transport speed becomes slower when the rotation speed of the dial is lowered.
In the case of the shuttle function or the variable function, the tape transport speed changes according to the rotation angle (rotation phase) of the dial. The tape transport speed is high if a phase difference from a rotation phase corresponding to a zero speed is large, and the tape transport speed is low if the phase difference is small.
Generally, the same dial is used for the jog function and the variable or shuttle function in common. The selection of these functions is changed from one over to the other by means of a change-over switch which is provided separately from the dial.
A difference between the variable function and the shuttle function is as follows: a function whereby a reproduced image having no noise bar is obtainable at any tape transport speed with a VTR designed for business use or the like is called the variable function. A function whereby a noise bar appears in a reproduced image when the image is reproduced at a high speed with a home VTR or the like is called the shuttle function.
Meanwhile, the VTRs of the kind having the shuttle function or the variable function are arranged in general to have the rotation angle (rotation phase) of the dial in a relation to the tape transport speed as shown in FIG. 1. As shown, the tape transport speed changes from one speed over to another every time the rotation angle of the dial changes a given degree.
In a case where the VTR is arranged to permit the tape transport speed to be set at any of many different speeds, a range of dial rotation angles (rotation phases) corresponding to each tape transport speed becomes extremely narrow. In such a case, therefore, the tape transport speed changes when the dial is turned only to a very small degree. Hence, the dial operation has been very difficult for the user in setting the tape transport speed at a desired speed value.